Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes

P.A.R Ade; R Adam; N. Aghanim; M. Arnaud; J. Aumont; C. Baccigalupi; A.J. Banday; R.B. Barreiro; J.G. Bartlett; N. Bartolo; Per Rex Christensen; Pavel Nasselski; Igor Dmitrievich Novikov; Anne Mette Frejsel; Hans Ulrik Nørgaard-Nielsen

doi:10.1051/0004-6361/201425034

Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes

P.A.R Ade, R Adam, N. Aghanim, M. Arnaud, J. Aumont, C. Baccigalupi, A.J. Banday, R.B. Barreiro, J.G. Bartlett, N. Bartolo, Per Rex Christensen, Pavel Nasselski, Igor Dmitrievich Novikov, Anne Mette Frejsel, Hans Ulrik Nørgaard-Nielsen

Theoretical high energy, astroparticle and gravitational physics

185 Citations (Scopus)

Abstract

The polarized thermal emission from diffuse Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100 GHz. In this paper we exploit the uniqueness of the Planck HFI polarization data from 100 to 353 GHz to measure the polarized dust angular power spectra C_ℓ^EE and C_ℓ^BB over the multipole range 40 < ℓ < 600 well away from the Galactic plane. These measurements will bring new insights into interstellar dust physics and allow a precise determination of the level of contamination for CMB polarization experiments. Despite the non-Gaussian and anisotropic nature of Galactic dust, we show that general statistical properties of the emission can be characterized accurately over large fractions of the sky using angular power spectra. The polarization power spectra of the dust are well described by power laws in multipole, C_ℓ ∝ ℓ^α, with exponents α^EE,BB = -2.42 ± 0.02. The amplitudes of the polarization power spectra vary with the average brightness in a way similar to the intensity power spectra. The frequency dependence of the dust polarization spectra is consistent with modified blackbody emission with β_d = 1.59 and T_d = 19.6 K down to the lowest Planck HFI frequencies. We find a systematic difference between the amplitudes of the Galactic B- and E-modes, C_ℓ^BB/C_ℓ^EE = 0.5. We verify that these general properties are preserved towards high Galactic latitudes with low dust column densities. We show that even in the faintest dust-emitting regions there are no "clean" windows in the sky where primordial CMB B-mode polarization measurements could be made without subtraction of foreground emission. Finally, we investigate the level of dust polarization in the specific field recently targeted by the BICEP2 experiment. Extrapolation of the Planck 353 GHz data to 150 GHz gives a dust power D_ℓ^BB ≡ ℓ(ℓ +1)C_ℓ^BB/(2π) of 1.32 × 10^-2 μK_CMB² over the multipole range of the primordial recombination bump (40 < ℓ < 120); the statistical uncertainty is ± 0.29 × 10^-2 μK_CMB² and there is an additional uncertainty (+0.28, -0.24) × 10^-2 μK_CMB² from the extrapolation. This level is the same magnitude as reported by BICEP2 over this ℓ range, which highlights the need for assessment of the polarized dust signal even in the cleanest windows of the sky.

Original language	English
Article number	A133
Journal	Astronomy & Astrophysics
Volume	586
ISSN	0004-6361
DOIs	https://doi.org/10.1051/0004-6361/201425034
Publication status	Published - 1 Feb 2016

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Ade, P. A. R., Adam, R., Aghanim, N., Arnaud, M., Aumont, J., Baccigalupi, C., Banday, A. J., Barreiro, R. B., Bartlett, J. G., Bartolo, N., Christensen, P. R., Nasselski, P., Novikov, I. D., Frejsel, A. M., & Nørgaard-Nielsen, H. U. (2016). Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes. Astronomy & Astrophysics, 586, [A133]. https://doi.org/10.1051/0004-6361/201425034

Ade, PAR, Adam, R, Aghanim, N, Arnaud, M, Aumont, J, Baccigalupi, C, Banday, AJ, Barreiro, RB, Bartlett, JG, Bartolo, N, Christensen, PR , Nasselski, P, Novikov, ID, Frejsel, AM & Nørgaard-Nielsen, HU 2016, 'Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes', Astronomy & Astrophysics, vol. 586, A133. https://doi.org/10.1051/0004-6361/201425034

@article{e68c2068be6045d0bf8d6ebcc3bcd41c,

title = "Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes",

abstract = "The polarized thermal emission from diffuse Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100 GHz. In this paper we exploit the uniqueness of the Planck HFI polarization data from 100 to 353 GHz to measure the polarized dust angular power spectra CℓEE and CℓBB over the multipole range 40 < ℓ < 600 well away from the Galactic plane. These measurements will bring new insights into interstellar dust physics and allow a precise determination of the level of contamination for CMB polarization experiments. Despite the non-Gaussian and anisotropic nature of Galactic dust, we show that general statistical properties of the emission can be characterized accurately over large fractions of the sky using angular power spectra. The polarization power spectra of the dust are well described by power laws in multipole, Cℓ ∝ ℓα, with exponents αEE,BB = -2.42 ± 0.02. The amplitudes of the polarization power spectra vary with the average brightness in a way similar to the intensity power spectra. The frequency dependence of the dust polarization spectra is consistent with modified blackbody emission with βd = 1.59 and Td = 19.6 K down to the lowest Planck HFI frequencies. We find a systematic difference between the amplitudes of the Galactic B- and E-modes, CℓBB/CℓEE = 0.5. We verify that these general properties are preserved towards high Galactic latitudes with low dust column densities. We show that even in the faintest dust-emitting regions there are no {"}clean{"} windows in the sky where primordial CMB B-mode polarization measurements could be made without subtraction of foreground emission. Finally, we investigate the level of dust polarization in the specific field recently targeted by the BICEP2 experiment. Extrapolation of the Planck 353 GHz data to 150 GHz gives a dust power DℓBB ≡ ℓ(ℓ +1)CℓBB/(2π) of 1.32 × 10-2 μKCMB2 over the multipole range of the primordial recombination bump (40 < ℓ < 120); the statistical uncertainty is ± 0.29 × 10-2 μKCMB2 and there is an additional uncertainty (+0.28, -0.24) × 10-2 μKCMB2 from the extrapolation. This level is the same magnitude as reported by BICEP2 over this ℓ range, which highlights the need for assessment of the polarized dust signal even in the cleanest windows of the sky.",

author = "P.A.R Ade and R Adam and N. Aghanim and M. Arnaud and J. Aumont and C. Baccigalupi and A.J. Banday and R.B. Barreiro and J.G. Bartlett and N. Bartolo and Christensen, {Per Rex} and Pavel Nasselski and Novikov, {Igor Dmitrievich} and Frejsel, {Anne Mette} and N{\o}rgaard-Nielsen, {Hans Ulrik}",

year = "2016",

month = feb,

day = "1",

doi = "10.1051/0004-6361/201425034",

language = "English",

volume = "586",

journal = "Astronomy and Astrophysics Supplement Series",

issn = "0004-6361",

publisher = "E D P Sciences",

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TY - JOUR

T1 - Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes

AU - Ade, P.A.R

AU - Adam, R

AU - Aghanim, N.

AU - Arnaud, M.

AU - Aumont, J.

AU - Baccigalupi, C.

AU - Banday, A.J.

AU - Barreiro, R.B.

AU - Bartlett, J.G.

AU - Bartolo, N.

AU - Christensen, Per Rex

AU - Nasselski, Pavel

AU - Novikov, Igor Dmitrievich

AU - Frejsel, Anne Mette

AU - Nørgaard-Nielsen, Hans Ulrik

PY - 2016/2/1

Y1 - 2016/2/1

N2 - The polarized thermal emission from diffuse Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100 GHz. In this paper we exploit the uniqueness of the Planck HFI polarization data from 100 to 353 GHz to measure the polarized dust angular power spectra CℓEE and CℓBB over the multipole range 40 < ℓ < 600 well away from the Galactic plane. These measurements will bring new insights into interstellar dust physics and allow a precise determination of the level of contamination for CMB polarization experiments. Despite the non-Gaussian and anisotropic nature of Galactic dust, we show that general statistical properties of the emission can be characterized accurately over large fractions of the sky using angular power spectra. The polarization power spectra of the dust are well described by power laws in multipole, Cℓ ∝ ℓα, with exponents αEE,BB = -2.42 ± 0.02. The amplitudes of the polarization power spectra vary with the average brightness in a way similar to the intensity power spectra. The frequency dependence of the dust polarization spectra is consistent with modified blackbody emission with βd = 1.59 and Td = 19.6 K down to the lowest Planck HFI frequencies. We find a systematic difference between the amplitudes of the Galactic B- and E-modes, CℓBB/CℓEE = 0.5. We verify that these general properties are preserved towards high Galactic latitudes with low dust column densities. We show that even in the faintest dust-emitting regions there are no "clean" windows in the sky where primordial CMB B-mode polarization measurements could be made without subtraction of foreground emission. Finally, we investigate the level of dust polarization in the specific field recently targeted by the BICEP2 experiment. Extrapolation of the Planck 353 GHz data to 150 GHz gives a dust power DℓBB ≡ ℓ(ℓ +1)CℓBB/(2π) of 1.32 × 10-2 μKCMB2 over the multipole range of the primordial recombination bump (40 < ℓ < 120); the statistical uncertainty is ± 0.29 × 10-2 μKCMB2 and there is an additional uncertainty (+0.28, -0.24) × 10-2 μKCMB2 from the extrapolation. This level is the same magnitude as reported by BICEP2 over this ℓ range, which highlights the need for assessment of the polarized dust signal even in the cleanest windows of the sky.

AB - The polarized thermal emission from diffuse Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100 GHz. In this paper we exploit the uniqueness of the Planck HFI polarization data from 100 to 353 GHz to measure the polarized dust angular power spectra CℓEE and CℓBB over the multipole range 40 < ℓ < 600 well away from the Galactic plane. These measurements will bring new insights into interstellar dust physics and allow a precise determination of the level of contamination for CMB polarization experiments. Despite the non-Gaussian and anisotropic nature of Galactic dust, we show that general statistical properties of the emission can be characterized accurately over large fractions of the sky using angular power spectra. The polarization power spectra of the dust are well described by power laws in multipole, Cℓ ∝ ℓα, with exponents αEE,BB = -2.42 ± 0.02. The amplitudes of the polarization power spectra vary with the average brightness in a way similar to the intensity power spectra. The frequency dependence of the dust polarization spectra is consistent with modified blackbody emission with βd = 1.59 and Td = 19.6 K down to the lowest Planck HFI frequencies. We find a systematic difference between the amplitudes of the Galactic B- and E-modes, CℓBB/CℓEE = 0.5. We verify that these general properties are preserved towards high Galactic latitudes with low dust column densities. We show that even in the faintest dust-emitting regions there are no "clean" windows in the sky where primordial CMB B-mode polarization measurements could be made without subtraction of foreground emission. Finally, we investigate the level of dust polarization in the specific field recently targeted by the BICEP2 experiment. Extrapolation of the Planck 353 GHz data to 150 GHz gives a dust power DℓBB ≡ ℓ(ℓ +1)CℓBB/(2π) of 1.32 × 10-2 μKCMB2 over the multipole range of the primordial recombination bump (40 < ℓ < 120); the statistical uncertainty is ± 0.29 × 10-2 μKCMB2 and there is an additional uncertainty (+0.28, -0.24) × 10-2 μKCMB2 from the extrapolation. This level is the same magnitude as reported by BICEP2 over this ℓ range, which highlights the need for assessment of the polarized dust signal even in the cleanest windows of the sky.

U2 - 10.1051/0004-6361/201425034

DO - 10.1051/0004-6361/201425034

M3 - Journal article

SN - 0004-6361

VL - 586

JO - Astronomy and Astrophysics Supplement Series

JF - Astronomy and Astrophysics Supplement Series

M1 - A133

ER -

Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes

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